The present invention relates to an assembly for controlling filling of the vehicle fuel tank having a filler neck. More particularly, the present invention relates to a fuel and fuel vapor handling system which controls a filling operation of a fuel tank and which controls the discharge of fuel vapors from the tank and the filler neck both during and after the filling operation.
A fuel cap with a sealing gasket typically is used to close the open end of a fuel tank filler neck. Once the fuel tank is filled and the fuel-dispensing nozzle is withdrawn from the filler neck, the fuel cap is reattached to the filler neck so that the sealing gasket forms a seal between the fuel cap and the filler neck. Thus, the fuel cap closes the open end of the filler neck to block discharge of liquid fuel and fuel vapor from the fuel tank through the filler neck. It is known however to place pressure relief and vacuum relief valves in fuel caps to permit some controlled venting of fuel vapors in the filler neck while the fuel cap is mounted on the filler neck.
It has been observed that fuel caps are often lost or damaged over time and, as a result, the open end of the filler neck might not be closed and sealed in accordance with the original equipment specifications during operation of the vehicle. Accordingly, a filler neck configured to "open" automatically to receive a fuel-dispensing pump nozzle therein during refueling and "close" automatically once the attendant withdraws the pump nozzle from the filler neck without requiring the attendant to reattach a fuel cap to the filler neck would be an improvement over many conventional capped filler-neck systems. Although conventional fuel caps function to close filler necks in a satisfactory manner, it is thought that a capless filler neck could make vehicle refueling more convenient for the consumer because no action other than inserting a pump nozzle into the open end of the filler neck would be required to refuel a vehicle. Advantageously, such a capless filler-neck system would be configured in accordance with the present invention to include internal liquid fuel and fuel vapor control means.
One object of the present invention is to provide a refueling system which does not require use of a conventional fuel cap.
Another object of the present invention is to provide a capless refueling system which is capable of maintaining acceptable fuel tank fill rates without premature shutoff of the fuel nozzle.
Yet another object of the present invention is to provide a refueling system which controls handling fuel vapor in the system both during and after the fuel refilling process.
Still another object of the present invention is to provide a system for automatically venting the fuel tank during refueling in response to insertion of a fuel-dispensing pump nozzle into a fuel tank filler neck. In one embodiment of the invention, the fuel tank is vented to the atmosphere, while in another embodiment of the invention, the fuel tank is vented to a canister for processing fuel vapor in an onboard, fuel-vapor recovery system.
Another object of the present invention is to provide an internal drain system for discharging water or other contaminants that might inadvertently leak into the filler neck from the filler neck to the ground underneath the vehicle to minimize the opportunity for such contaminants to be carried into the fuel tank through the filler neck during refueling.
Yet another object of the invention is to provide a nozzle shutoff system for controlling the pressure in the region of the filler neck containing the pump nozzle during refueling to control triggering shutoff of fuel flow from a pressure-actuated pump nozzle once the fuel tank is filled to a predetermined maximum volume to control filling of the fuel tank in such a way as to prevent overfilling of the fuel tank.
Still another object of the invention is to provide a pressure and vacuum relief system in a fuel tank filler neck which will enable the fuel tank to vent whenever a predetermined high pressure or a predetermined negative pressure exists within the fuel tank even when the filler neck is otherwise closed by its internal pump nozzle-actuated, filler-neck closure system.
According to the present invention, an assembly is provided for controlling filling of a vehicle fuel tank having a filler neck. The assembly includes means for conducting liquid fuel through a fill passageway to the filler neck for delivery to the fuel tank. The conducting means is formed to include means for admitting a fuel-dispensing nozzle therein to introduce liquid fuel into the conducting means. The conducting means also includes valve means for normally closing the fill passageway. The valve means is movable between a fill passageway-opening and a fill passageway-closing position. The assembly also includes valve control means for moving the valve means from its fill passageway-closing position to the fill passageway-opening position in response to movement of a fuel-dispensing nozzle into the fill passageway. The valve control means is situated in the fill passageway to engage the fuel-dispensing nozzle inserted therein. The valve control means is connected to the valve means.
In preferred embodiments of the present invention, the conducting means includes partition means for dividing the fill passageway into an outer chamber communicable with the atmosphere and an inner chamber in fluid communication with the filler neck. The partition means is formed to include an aperture interconnecting the outer and inner chambers in fluid communication. The valve means includes the closure member situated in the inner chamber and configured to close the aperture to block the flow of fluid from the outer chamber to the inner chamber upon movement of the valve means to its fill passageway-closing position.
Also in preferred embodiments, the valve means includes first spring means for yieldably biasing the closure member into engagement with the partition means to close the aperture interconnecting the inner and outer chambers. The valve control means includes means for engaging a fuel-dispensing nozzle inserted into the outer chamber and means for moving the closure member against a biasing force provided by the first spring means. The moving means moves the closure member from its normal position closing the aperture to a retracted position opening the aperture in response to movement of the fuel-dispensing nozzle in the outer chamber against the engaging means.
In preferred embodiments, the valve means is a spring-loaded fill valve or closure member sized to close an aperture provided in the fill passageway and the valve control means is a nozzle-actuated slide member coupled to the closure member. In operation, the distal end of the pump nozzle engages the slide member and moves the slide member in the fill passageway enough to cause the closure member to move against its biasing spring from a normally closed position to an aperture-opening position so that fuel is able to flow through the aperture and the remaining portion of the filler neck and into the fuel tank.
Also, in preferred embodiments, a normally-open contaminant drain valve is provided for controlling drainage of liquids from the outer chamber of the fill passageway to lessen the chance that such liquids could pass through the aperture into the fuel tank upon movement of the closure member to its aperture-opening position during refueling. Also, a normally-closed nozzle shutoff valve is provided for controlling delivery of make-up vapor from the fuel tank to the outer chamber during refueling so that the magnitude of pressure in the outer chamber around the automatic shutoff sensor on the pump nozzle exceeds the magnitude of negative pressure needed to trigger that sensor and automatically shut off fuel delivery through the pump nozzle only when the volume of liquid fuel in the fuel tank is fully filled. Further, a normally-closed tank venting valve is provided for venting the fuel tank to the atmosphere. In the illustrative embodiment, the normally-open contaminant drain valve is closed, the normally-closed nozzle shutoff valve is opened, and the normally-closed tank venting valve is opened in response to movement of the slide member to open the normally closed fill valve or closure member during insertion of the pump nozzle into the filler neck to begin the refueling process.
Additional objects, feature, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.